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(1) Field of the Invention
The present invention relates generally to industrial refrigeration systems, and more particularly to an improved dry suction ammonia refrigeration system having a desuperheating coil, a modified accumulator, and a specially shaped and located purge connection.
(2) Background Information
A major drawback of industrial and commercial refrigeration systems which utilize ammonia as a refrigerant is a high cost of installation, operation, and maintenance. Conventional two stage refrigeration systems utilize a first stage which will provide refrigerant gas having a pressure of about 15 inches HG-0 psig from a low stage accumulator to a compressor, which will compress the gas to approximately 25-30 psi and discharge the compressed gas to a desuperheating coil, then through an oil separator to the second stage. The second stage will take this pressurized gas through a second compressor which increases the pressure to approximately 185 psig. This high pressure gas is then run through a condenser.
The inventors herein have found that a reduction in the heat of the gas through a desuperheating coil prior to running the gas through a second compressor, reduces the horse power required to compress the gas in the second stage compressor, and also extends the life of the compressor. This in turn results in reduced maintenance, wear, and overall cost and efficiency of the refrigeration system.
It is therefore a general object of the present invention to provide an improved ammonia refrigeration system.
A further object is to provide an improved ammonia refrigeration system which reduces operating costs, installation costs, and maintenance costs as compared to conventional ammonia refrigeration systems.
Another object of the present invention is to provide an improved ammonia refrigeration system with a desuperheating coil located and connected so as to reduce the horse power required to compress the gas in the system.
Yet another object is to provide a refrigeration system with an improved accumulator design.
Still another object of the present invention is to provide an improved refrigeration system with a tee purge connection located to permit purging of gas downstream of the condenser.
Yet a further object of the present invention is to provide an improved refrigeration system which reduces operating costs, installation costs, and maintenance costs as compared to conventional refrigeration systems.
These and other objects of the present invention will be apparent to those skilled in the art.
The improved refrigeration system of the present invention includes an accumulator with a diffuser and velocity reducer pipe extending downwardly into the upper end of a vapor refrigerant tank, the return pipe extending from an evaporator and discharging vapor refrigerant therefrom into the tank. The diffuser pipe includes a lower end located within the interior of the tank which is expanded in diameter relative to the upper end, thereby reducing the velocity of fluid flowing through the pipe and entering the accumulator tank. A diffusion plate is mounted in the diffuser pipe, to further diffuse fluid flowing therethrough.
The improved refrigeration system also includes a tee having a stem portion extending horizontally from the condenser of the system, and a pair of upper and lower arms connected in a vertical orientation to the stem. The tee lower arm is connected to the receiver and the upper arm is connected to a purge connection. This allows for a positive separation and accumulation of noncondensable gases.
The improved refrigeration system further includes a two stage refrigeration system with the condenser of the high stage having a second section with a desuperheating coil therein to cool vapor refrigerant from the low stage compressor and supplying it to the high stage accumulator.